We investigate highly polydisperse packings subjected to simple shear by contact dynamics simulations. A major unsolved issue is how granular texture and force chains depend on the size polydispersity and how far they influence the shear strength. The numerical treatment was made possible by ensuring the statistical representation of particle size classes. An unexpected finding is that the inte...

We analyze the shear strength and microstructure of binary granular mixtures consisting of disks and elongated particles by varying systematically both the mixture ratio and degree of homogeneity (from homogeneous to fully segregated). The contact dynamics method is used for numerical simulations with rigid particles interacting by frictional contacts. A counterintuitive finding of this work is...

there are limitations in experimental studies on sand-gravel mixtures due to the small size of testingspecimens. due to this problem, many researchers have worked on prediction of the shear strength of mixture by testingthe sandy fraction of soil alone and developed empirical relationships. most of the previous relationships have beendetermined for low surcharge pressures in which particle brea...

This paper presents the results of a laboratory investigation to determine the geotechnical properties of fresh municipal solid waste (MSW) collected from the working phase of Orchard Hills Landfill located in Davis Junction (Illinois, USA). Laboratory testing was conducted on shredded MSW to determine the compaction, hydraulic conductivity, compressibility, and shear strength properties at in-...

-Theoretical constraints on the stress-dilation relation for a deforming Coulomb material require v -< 0 if C = 0 and v -< sin-l(Tm/e,n) always, where v is the dilation angle, 0 is the friction angle, C is cohesion, z,, is the maximum shear stress, and a,~ is the mean effective stress. Recent laboratory measurements of friction and dilatancy of simulated fault gouge show that small amplitude sh...

The main purpose of this paper is to compare the predictions of four laws currently used for the estimation of the wall shear stress in an incompressible turbulent boundary layer-viz., A proposal is also made for a modified skin-friction law which would appear to predict values of the wall shear stress to within about 5 percent over its range of validity. A feature of this new law is that close...

A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting is described consistently. Dependences of friction force on tempe...

High dry friction requires intimate contact between two surfaces and is generally obtained using soft materials with an elastic modulus less than 10 MPa. We demonstrate that high-friction properties similar to rubberlike materials can also be obtained using microfiber arrays constructed from a stiff thermoplastic (polypropylene, 1 GPa). The fiber arrays have a smaller true area of contact than ...

[1] We examine the frictional behavior of a range of lithified rocks used as analogs for fault rocks, cataclasites and ultracataclasites at seismogenic depths and compare them with gouge powders commonly used in experimental studies of faults. At normal stresses of ∼50 MPa, the frictional strength of lithified, isotropic hard rocks is generally higher than their powdered equivalents, whereas fo...